Ayan ke roop mein Krishn hai, Krishn ke roop mein nahi.
It's very complicated.
Think about it this way.
You have Ramu. You also have Tina. R and T are janamon ke saathi, hum saath saath hai vala friends, pyaar vyaar ishq mohabbat, sache prem people (minus the original "Prem" Sallu bhai) etc..
One day Ramu dresses up like a donkey and goes to Tina's place to have fun. He introduces himself as Shamu, Ramu's non-existent twin brother. Tina's dad believes Shamu is cuter (because Tina's dad is a gadhe ke bachche, so naturally he will like Ramu as Shamu).
Eventually, Tina gets married to Shamu (which is Ramu dressed up as a donkey). Even though Ramu is Shamu, he can never reveal himself because Tina's dad will kill him.
Similarly, StarKrishna is crying because he can't be with his Radha, despite being with his Radha. His and Ramu's conditions are the same. But since Radha is in concern, KRISHNA as Ayan would fight with KRISHNA as Krishn to make sure that he, Krishn as Ayan, gets Radha ... instead of Krishn as Krisha. Both are the same, they both love Radha, so their fight for Radha is genuine and pure. So he is crying that his life is so wretched that he couldn't marry Radha, even though he, as Ayan, is marrying Radha.
Since I know you very well, I have some backup theories as well.
Theory 2: StarKrishna is only crying out of happiness, seeing Ayan as Krishn getting married to Radha. Since he and Ayan are the same, he's feeling Ayan as KRISHNA's bliss of getting married. Kushiyon ke aanshu hai.
Theory 3: StarKrishna is crying because he is super happy that Ayan is getting married. Now the rasa between Radha-KRISHNA can intensify because meeting choopa-choopi style > marriage.
Jhanak
